Nowadays, the functions of various electronic products become more powerful. Since handheld devices are increasingly popular, the demands on the data transmission between various electronic products or handheld devices are increased. As the volume of the electronic product or the handheld device is gradually reduced, there is a need of installing more connecting interfaces (e.g. connectors or the complementary connectors) on the casing's peripheral profile (also referred as a casing's coastline) of the electronic product or the handheld device so as to exchange signals between different devices. For example, the connector is an electrical plug, and the complementary connector is an electrical receptacle (also referred as a connecting port).
Nowadays, the connectors with universal serial bus (USB) interfaces become the mainstream of the commercially available connectors. According to specifications, the connectors with the USB interfaces are classified into three types, including a USB Type-A (or USB-A) connector, a USB Type-B (or USB-B) connector and a USB Type-C (or USB-C) connector. Nowadays, the USB-A ports of most electronic devices comply with the USB 3.0 communication standard. Generally, the electronic device with the USB 3.0 interface is only able to provide a current of about 900 mA. As known, the use of a single USB-A connector cannot provide sufficient electricity to the high power consumption device.
On the other hand, USB-C interfaces are designed according to the USB 3.1 communication standard. The USB-C interface can withstand the current of 5 ampere (A) at 20V and transfer the electric power of 100 W. Especially, when the USB-C interface is applied to the USB power delivery (USB PD) technology, the USB-C interface can support the charging/discharging functions in the voltage range between 5V and 20V and in the current range between 0V and 5V. Moreover, the magnitudes of the voltage and the matching current may be selected according to the practical requirements. In other words, the USB-C connector can provide more electricity. Consequently, most novel electronic devices use USB-C connectors as the charging interfaces.
Since the USB ports of most electronic devices (e.g., computer hosts) are USB-A ports, some drawbacks occur. For example, the electronic devices with the USB-C ports are not popular. For connecting the electronic device with the USB-C connector to another electronic device with the USB-A port, an additional USB-C to USB-A adapter is necessary. However, even if the USB-C to USB-A adapter is employed, the electronic device with the USB-A port is only able to output or receive the lower current (e.g., 900 mA). In other words, the commercially available USB-C to USB-A adapter cannot provide sufficient electricity.